New Delhi: Prime Minister Narendra Modi on Monday hailed as “major achievement” the completion of first deterrence patrol by India’s first indigenous nuclear submarine INS Arihant.

Addressing the INS Arihant’s crew which returned from its first deterrence patrol, the prime minister said, “The success of INS Arihant is a big step towards strengthening national security. For the country’s enemies, it is an open challenge.”

In a series of tweets, the prime minister said that the nuclear submarine enhances country’s security needs and will protect it from “external threats”.

“Dhanteras gets even more special! India’s pride, nuclear submarine INS Arihant successfully completed its first deterrence patrol! I congratulate all those involved, especially the crew of INS Arihant for this accomplishment, which will always be remembered in our history,” tweeted PM Modi.

“The success of INS Arihant enhances India’s security needs. It is a major achievement for our entire nation. True to its name, INS Arihant will protect the 130 crore Indians from external threats and contribute to the atmosphere of peace in the region,” said the prime minister.

Asserting that “credible nuclear deterrence is the need of the hour”, PM Modi said that “success of INS Arihant gives a fitting response to those who indulge in nuclear blackmail”.

“Today is historic because it marks the completing of the successful establishment of the nuclear triad. India’s nuclear triad will be an important pillar of global peace and stability,” tweeted PM Modi.

“India is a land of peace. Values of togetherness are enshrined in our culture. Peace is our strength, not our weakness. Our nuclear programme must be seen with regard to India’s efforts to further world peace and stability,” he added.

INS Arihant was commissioned into Indian Navy in August 2016 and completed India’s nuclear triad. The submarine can carry either 12 nuclear-tipped 750-km range K-15 Sagarika short range Sea Launched Ballistic Missiles (SLBMs) or four 3500-km range K4 SLBMs, which can be fired from four vertical launch tubes.

The 112-metre log, 6,000-tonne INS Arihant is powered by a 83 MW pressurised light water reactor and has been built under the Advanced Technology Vessel (ATV) project at the Ship Building Centre in Visakhapatnam, one of the key bases of Indian Navy.

India joined a select group of five nations – USA, Russia, China, France and the UK – to build and operate a SSBN with the commissioning of INS Arihant. The second SSBN under ATV project, INS Aridhaman, is undergoing sea trials. The submarine will be commissioned into the Navy only by 2019 and its nuclear reactor will go critical only after sea trials.